Refrigerating system



Aug. 15, 1944.

W. A. RAY

REFRIGERATING SYSTEM Filed vSept. 4, 1942 5 sheets -sheet 1 Condenser 41 Pressure Respansive INVENTOR ATTORNEY Aug. 15, 1944. w A RAY 2,355,894

REFRIGERATING SYSTEM Filed Sept. 4, 1942 3 Sheets-Sheet 2 INVENTORiV/fl/am ,4. Fa

ATTORNEY Aug. 15, 1944. w, R Y

REFRIGERATING SYSTEM C'zSheets-Sheet 5 Filed Sept. 4; 1942 INVENTOR[William ,4. F0

4 f TTORNEY of the valve. quent intervals, to permit small successivePatented Aug. 15, 1944 UNITED STATES PATENT OFFICE REFRIGERATING SYSTEMWilliam A. Ray, Glendale, Calif.

Application September 4, 1942, Serial No. 457,302

3 Claims.

This invention relates to a mechanical refrigerating system.

Such systems almost invariably rely upon the absorption of heatattendantupon a change of state of a refrigerant from liquid to gaseous.[The vaporization of the liquid refrigerant is accomplished byconducting it to a space where the pressure is low. This low pressurereduces the boiling point temperature of the refrigerant below that towhich the refrigerant is subjected. Accordingly the liquid quicklyvaporizes, and heat is absorbed in the process. 5

The evaporation space where the change of state occurs is usually anexpansion coil formed of tubing. After evaporation, the vapor or gas isconducted to the inlet of a compressor, where the gas is placed underhigh pressure; then the gas is conducted to a condenser, Where the gasis cooled below its condensing point and reverts to a liquid. From thecondenser the liquid refrigerant is then conducted at intermittentperiods as required, to the expansion space.

()ne of the factors determining th degree of refrigeration is the rateat which the liquid refrigerant is passed to the evaporator. In manysystems the control of the passage of the refrigerant to the evaporatoris performed by an expansion valve, operated automatically in accordancewith pressure differentials on opposite sides Such a valve is operativeat frecharges of refrigerant to pass to the evaporator. The automaticcontrol of the valve is maderesponsive to predetermined conditions, suchas temperature of the space being cooled, the pressure or temperature ofthe refrigerant in a specified part of the cycle of refrigeration, orcombinations thereof. With a usual form of expansion valve, suchautomatic controls are quite complex, and therefore apt to be unreliablein extended service.

It is one of the objects of this invention to provide a simplifiedcontrol apparatus for a refrigerator system.

This object is accomplished, in the present instance, by providing asimple electric control circuit for the valve that controls the passageof the refrigerant to' the vaporizer. Thus it is another object of thisinvention to make it possible to utilize an electrically operated valveinstead of the usual expansion valve, for controlling the passa e ofrefrigerant to the vaporizer.

By providing such a valve, it is a relatively simple matter to arrange aseries control circuit therefor that is energized only when all of thecontrol factors are active. Accordingly it is another object of thisinvention to make it possible to control an electrically operated valvein response to the simultaneous occurrence of controlling factors, suchas temperatures and pressures.

In the present instance, one of the controlling factors is the degree ofsuperheat of the vaporized refrigerant adjacent the outlet of thevaporizer; that is, the difference betwen the boiling point temperatureof the liquid refrigerant and the actual temperature of the gas. Anothercontrolling factor is the temperature of the space being cooled.

A refrigerating system, as heretofore explained, requires frequentoperation of the valve that admits refrigerant to the vaporizer. Itisanother object of this invention to make it possible, in a refrigeratingsystem of this character, to provide a valve that can operate millionsoftimes in succession during its useful life.

When an expansion valve is used, the opening of the valve port may bequite gradual, thereby causing wire drawing, which has a destructiveeffect upon the valve seats. It is another object of this invention toprevent such wire drawing, especially by ensuring that the valve willquickly open and close, without the possibility that the valve willremain in only a. partially opened condition. This snap action is mostconveniently provided by an electromagnetically operated valve, which isarranged to move the closure member from closed to open position as soonas the valve is energized. Instead of a. soft or slow seating, the valveclosure is seated with a gentle blow, with correspondingly betterseating action.

It is a simple matter with such a valve, to pro vide a relatively shortstroke for the closure. This limits the velocity and inertia effects ofthe closure movement, and accordingly destructive valve seatingvelocities are avoided. The life of the valve is thus further increased.

In such an electromagnetically operated valve, the lift of the closurecan be so arranged that it is constant, providing a constant valveopening area sufilcient to eliminate all danger of wire drawing. Inorder nevertheless to make it possible to predetermine the rate at whichthe refrig erant is to pass to the vaporizer, a throttling oriflee canbe used; and the size of this orificecan be selected to suit therequirements of the system.

It is still another object of the invention therefore, to provide avalve operating only between a. fully open and a fully closed position.with its and ttendant advantages, and yet to make it posible to selectthe rate of supply of refrigerant to e vaporizer.

In the usual time of expansion valve that has been incorporatedrefrigerating systems, the pressures that are effective on oppositesides of the valve closure necessitate a comparatively large andcumbersome structure. By using an electromagnetically operated valve, inwhich fluid pressures on the valve closure have no direct regulating orcontrolling function, the size of the valve can be rastically reduced.

This invention possesses many other advantages, and has other objectswhich may be made more easily apparent from a consideration of severalembodiments of the invention. For this purpose there are shown a fewforms in the drawings accompanying and forming part of the presentspecification. These forms will now be described in detail, illustratingthe general principles of the invention; but it is to be understood thatthis detailed description is not to be taken in a limiting sense, sincethe scope of the invention is best defined by the appended claims.

In the drawings:

Figure l is a diagrammatic illustration of a system incorporating theinvention;

Fig. 2 is an enlarged elevation, partly in vertical section, of anelectromagnetically operated valve utilized in connection with thesystem;

Fig. 3 is a plan view of the valve seat member utilized in connectionwith the valve illustrated in Fig. 2;

Fig. 4 is a longitudinal sectional view of a control device utilized inconnection with the system;

Fig. 5 is a. sectional view, similar to Fig. 4, of a modified form ofthe device; and

Fig. 6 is a fragmentary sectional view taken along plane 66 of Fig. 4.

The system as illustrated in Fig. 1 includes an evaporator orvaporizerI, which may be in the form of convoluted tubing. This evaporator I maybe disposed in a space to be cooled, such as that formed by thecontainer 2. Liquid refrigerant is passed intermittently into theevaporator l as by the aid of an electrically operated valve 3. Thisvalve 3 has its inlet side connected to a condenser 4. This condenser 4in turn is connected with the outlet 5 of a compressor 6. The

inlet of the compressor is connected through a. conduit 7 to the outlet5| 0! a control device 8. The inlet 55 of the control device 8 isconnected to the outlet of vaporizer l.

The cycle of refrigeration consists of the admission of liquidrefrigerant through valve 3 into the vaporizer i, where the pressure issufliciently low to cause the refrigerant to vaporize. Any suitable typeof refrigerant may be used; for example, Freon. The gaseous refrigerant,after it has absorbed heat, passes through the outlet of vaporizer lthrough the control device 8, and is compressedby the compressor 6. Thecompressed refrigerant is then cooled by the aid of the condenser 4 soas to be reconverted into a liquid state. The recycling of a refrigerantthrough a closed system of this character is common. The novelty in thesystem resides in the manner in which the recycling is controlled.

The compressor 6 is shown in this instance as operated by an electricmotor 9. This electric motor is arranged to be supplied with electricalenergy from the mains Hi. If desired, an automatic pressure responsiveswitch H may be introduced in the motor circuit, whereby the compressorS is operated only upon occurrence of sumcient pressure on the inletside of the compressor 6.

The valve 3 is arranged to be electromagnetically operated. The circuitfor operating the valve 3 is automatically controlled in response to oneor more factors. Thus the control circuit can be in the form of a seriescircuit which includes a temperature responsive switch 12. This switchis so arranged that it responds to close the switch when the temperatureof the space within the container 2 reaches a limiting high value. Thecontrol of the valve 3 is furthermore effected through the controldevice 8 which controls the switch contacts l3. These contacts l3 are inseries with the temperature responsive switch 12. The switch It andswitch I: in series complete the circuit for the electromatlcallyoperated valve 3. The control device 8 is preferably one which causesclosing of the switch I! upon the occurrence of a definite condition ofthe refrigerant in the vaporizer I. For example the control may be madeto respond to a. definite excess in temperature of the refrigerant abovethat which corresponds to a saturated vapor at the pressure existing inthe vaporizer I. This excess temperature is usually designated as thedegree of super-heat.

Upon completion of the series circuit through both switch devices I: andII, the valve I is caused immediately to open fully, thus obviatingwire-drawing. This valve stays open until either the temperature of thespace in container 2 is reduced, or the superheat of the gaseousrefrigerant at the outlet side 01' the vaporizer I is reduced below adefinite value. For example, the superheat control member 8 may be soarranged that when the superheat reaches a value of 10 Fahrenheit, thecontacts ll close. Just as soon as enough liquid refrigerant is receivedin vaporizer l to reducethe super-heat, the switch ll opens and valve 3closes. Closing of the valve occurs immediately. Switch II remains openuntilthe refrigerant in the vaporizer reaches 10 of superheat. However,th valve 3 will remain closed unless the temperature switch I! is alsoclosed.

By controlling the valve 3 so that it is necessary for both thetemperature to reach a deflnite high limit and the super-heat to reach adefinite high limit, the refrigerating system can be operated in aneconomical fashion. Although this operation involves fairly rapidsuccessive operations of the valve 3, the structure of this valve issuch that this valve can operate successfully for extremely long periodsof time without requiring attention.

The valve 3 that controls the p ssage of liquid refrigerant to thevaporizer I is shown to best advantage in Figs. 2 and, 3. It is similarin design to a valve described and claimed in application Serial No.418,707, filed November 12, 1941, in the name of William A. Ray forFluid control valve.

The valve structure is shown as having a. valve body ll provided with aninlet passage II and an outlet passage II. The" inlet passagecommunicates with an annular space H formed bethe diameter of the bore2|. This main flange 2|, as shown most clearly in Fig. 3, may beinterrupted in order to provide a firm grip for a tool to turn the seatmember I! securely into place.

The seat member I3 in this instance is shown as provided with aplurality of ports 22. Each of these ports 22 is supplemented by atubular insert 23 defining a sharp edge forming the valve seat proper.

When the valve is opened, the liquid refrigerant flows into the spacethrough the inserts 23 into the space 24 within the boss Hi. Thepassageways for the liquid from the space 24 to the outlet |6 include anumber of ports 25, all communicating with the space 24. The lower endsof these ports communicate with the interior of a hollow boss 26. Thishollow boss is internally threaded for the accommodation of a cap member28. This cap member 28 is provided at its upper edge with a sealingflange 29, serving when the cap 28 is screwed into place, to seal theopening in the boss 26.

The cap 28 is arranged to accommodate a sleeve 36 that is provided witharestricted axial opening 3|. The liquid refrigerant, in its passage tooutlet I6, passes through this restricted opening 3|. By appropriatechoice of the size of the opening 3|, the rate. of flow of the liquidrefrigerant to the outlet I6 may be controlled.

In order to effect these results, the ports 24 communicate with theradial openings 32 in thesleeve 30, upwardly through the opening intothe outlet IS.

The sleeve 36 is purposely made removable so that it may be removed andanother sleeve substituted with an appropriate size of aperture 3|. Thesleeve 36 is held detachably in place by the aid of the compressionspring 34, urging the Thence the refrigerant can be flow 3| and a port33,

sleeve 3|! upwardly into a counterbore seat 35 disposed around the lowerend of the port 33.

The passage of liquid refrigerant is interrupted when a closure member36 is seated upon the seats 23. This closure member 36 is of diskllkeform. It is seated by its own weight, as well as by the force of acompression spring 31. This compression spring is shown as accommodatedin a cage 38 supported centrally of the disk 36, and extending below it.

The disk 36 has a diameter slightly less than 39 in the upper part ofbody M. In this way, transverse movement of the disk 36 is limited.

The disk 36 is made of magnetic material so that it may be lifted fromseats 23 by electro; magnetic action, as by energization of anelectromagnet. For this purpose use is made of an electromagnetincluding a coil 40. This coil is supported within a casing 42 that is apart of the magnetic circuit and thus forms an "ironclad type of-magnet.An annular space for accommodating 'coil 46 is provided between the coreor pole piece 4| and the casing 42. The lower edge of casing 42 isarranged to be seated upon a shoulder 43 disposed at the upper end ofthe body I4. It may be held in fluid tight relation with respect to thebody H as by the aid of a ring 44 seated on top of the shoulder 45formed on the bottom of the casing 42. The ring 45 may be urged intosealing position by the aid of a plurality of bolts 46. v

It is desirable to isolate the electromagneti I1 and then downwardlycoil 40 from the liquid refrigerant. For this purshoulder 43. A springguide 48 for the compression spring 31 is shown as bearing against thelower surface of the diaphragm 41. Furthermore, the coil 40 may be heldin place by the aid of the insulation ring 49 disposed over the coil andbetween the outer wall of casing 42 and the core 4|.

Any conventional type of electric coupling means 56 may be utilized forcarrying the terminals of the coil 46 externally of the iron-cladelectromagnet. When the coil 40 is energized, the disk 36 is attracted,because it forms a part of the magnetic circuit between the exteriorwall of the casing 42 and the core 4|. Apertures 5| may be providedthrough the disk 36 to ensure against any material dash pot action.

In order to ensure that a very large number of valve operations may besecured without wearing down the valve seat; provisions are made, asexplained in the application hereinabove referred to, for limiting thetilt of the disk49. In the present instance this tilt limiter is in theform of a raised flange 52 formed integrally with the seat member l9 andshown as concentric therewith. The upper surface of this flange 52 isdisposed only slightly below the lower surface of the disk 36; of theorder of one or, two thousandths of an inch. This clearance is shownexaggerated for the sake of clarity. Since this clearance is very small,the degree of tilt upon the valve seat is limited to a very small angle,before the limiting surface of flange 42 is contacted and the disk 36completely lifted from the seat.

The lift of the valve closure 36 is quite small. Accordingly only agentle blow occurs upon the seats 23 when the valve closure drops.Furthermore, the closure can assume only two operating positionscorresponding to fully open or fully closed; positions. The throttlingaperture 3| actually determines the rate at whichrefrigerant can pass tovaporizer I.

As before stated, the energization of the coil 40 for operating thevalve 3 is made dependent upon simultaneous occurrence of two factors.One of these factors is the closing of the temperature responsive switchI2. The other is the closing of the switch I3 in response to asuperheated condition of the gaseous refrigerant in vaporizer Themechanism 8 whereby superheat control of the contacts l3 may be securedis illustrated in Figs. 4 and 6.

A thin exterior wall 53 of non-magnetic material serves to define aspace 54 in communication with the outlet of the vaporizer The space 54is further in communication with the inlet of compressor 6 by the aid ofthe conduit 56.

The space 54 is otherwise made fluid tight as by the aid of the upperand lower heads 51 and 58. The upper head 51 is shown as provided withthe threaded bosses 59 and 60 into which the conduits 55 and 56 may befastened. The head 51 is held in fluid tight relation with the flange 6|Similarly, the lower head 58 is held in sealed relationship to the lowerend of the wall 53 by the aid of a flange 63 permanently attached to thelower end of wall 53.

The temperature of the refrigerant in the space 54 is caused to affect afeeler bulb or pressure cell 64 that is located in space 54. In turn,appropriate variation in the volume of the cell 84 will cause operationof switch 13.

Pressure cell 64 18 shown as formed by the aid of a corrugated flexiblewall 65. The upper end of the wall 65 is permanently attached and sealedto the lower side of the head 51. Its lower end is sealed by the endflange 66. A threaded aperture in the head 51 is sealed by plug 61 and.forms a convenient means for gaining access to the interior of the cell84. Located within this pressure cell 64 is a body of vaporizable liquid68. This vaporizable liquid may be of the same kind as the liquidrefrigerant used in the system, such as Freon or the like.

The pressure cell 54 is made to respond to variations in temperature ofthe refrigerant in space 54. For this purpose the wall 65 is purposelymade thin and of good heat conducting material.

As the temperature of the refrigerant increases, the pressure within thecell 64 increases correspondingly, and its volume increase. The endflange 66 is therefore urged downwardly. It is this motion of the endflange 56 that controls the operation of the contacts I3. I

In order to adjust the degree of superheat be-' fore the control effecttakes place, the downward movement of the end flange 66 is opposed by anadjustable spring force. This is effected for example by the aid of thecompression spring 59. The upper end of this compressionsprln abuts thelower side or the end flange 66. Its lower end rests upon an adjustableabutment 10. This adjustable abutment is carried on top of a corrugatedwall H. The lower end of this flexible wall it is in sealed relationwith the inner surface of the head 58. The position of the abutment 70is controlled by a manually adjustable set screw '52. This set screw isthreaded through the head 53. A checl: nut 32 may be provided for theset screw '32. The upper end '52 of the set screw is provided with arounded surface to be accommodated in a corresponding seat in theadjustable abutment "50.

he flexible ensures against leakage "refrige t past the screw 1;.

erant in space attains a suft temperature, as may be determined by thesetting of screw $2, the pressure cell 64 expands sufrlciently tooperate a bell crank lever 14, as by a slot and pin connection 100. Thisbell crank lever is pivoted on stationary pivot formed on a bracket 5'6fastened on the inside of wall 23. The lower arm or" hell crank lever'54 carries an armature l? made from magnetic material. This magneticarmature, when it approaches the well 53, passes into the influence of apermanent magnet it that is located exterior of the wall 5 3. Thispermanent magnet 78 is movabl mounted, as by a strip is to a flexiblespring arm 83. The spring arm 80is flexed toward wall 53, by theattraction between the armature H and the permanent magnet 18. By thismagnetic means therefore, the operation of the cell 84 inside ofthespace 54 may be caused to affect the external arm 80.

This spring arm carries at its lower end one of the contacts 8i of theset of contacts I3. The other contact 82, as shown most clearly in Fig.6, is mounted on the end of a screw 83. This screw 83 is fastened into aconducting support 84 attached'to the lower side of the head 58.Connection is made to the contact point 82 as by'the binding post 85.

The upper end of arm 80 is shown as anchored to the projection 86 formedintegrally with the flange 6|. It is insulated, however, from theprojection 86 and is provided with an upwardly ex tending portion 01.This portion 81 serves as a terminal for the spring arm 80, and thecontact II.

In the form of the control device Just described, the control of thecontacts I3 is effected by magnetic forces. This is necessary in orderto transmit the control effect of the enclosed pressure inside of thecasing wall 53 to the outside thereof. The magnetic effect isadvantageous also for the additional reason that upon withdrawal of thearmature 11, from the influence of magnet 18, the spring 80 quicklysnaps to open position.

The forces acting on the end wall 86 include the pressure of thesaturated vapor in cell 64, and the opposing pressure of spring 69. afurther opposing pressure due to the vapor pressure of the refrigerantin space 54, assisting the action of spring 8!. The vapor in cell 84being saturated at all times, exerts vapor pressure curve. But in thespace 54, if the refrigerant gas therein is unsaturated, the pressurecorresponding to the temperature is less than in cell 64. The spring 68can however readily be adjusted to provide a force that keeps lever 14in the inactive position of Fig. 4 until a definite temperature isreached. Such a setting of the spring 68 is entirely acceptable to causethe device 8 to operate at a definite degree of superheat if conditionsare such that the pressure in the outlet of vaporizer l keeps fairlyconstant. If the pressure varies substantially, a new adjustment ofspring 69 may be necessary to provide the controlling function at thedesired point of superheat.

In the form of switch is obviated.

The pressure cell ll in this case is formed of end flange 9!,corresponding to the end flange 88 of the form illustrated in Fig. 4.The cell 8| thus has an annular space 92 defined by the walls 89 for.

The internal surface of the inner wall 90 is open to the atmosphere,as-well as a portion of the top surface of the end flang II.

The ratio of the Variations in pressure of the refrigerant in space 99are automatically compensated for. Switch 51 closes when the pressure incell 88 reaches a value corresponding to the desired superheat.

In operation, the valve 3 may open and close quite often. A completecycle, consisting of the admission of refrigerant through valve 3 to thevaporizer I, the consequent lowering of the degree of superheat, theclosing of the valve 3 and subsequent rise of the degree of superheatmay occur as often as ten times per minute.

In the event the dissipation of heat from the space in container 2 isvery slow, then these cycles are discontinued until thermostat switch l2closes. I

What is claimed is:

1. In a device of the character described, a refrigerant container; asealed pressure cell having a flexible wall exposed to the temperaturewithin the container, and having as well an end wall adapted to be movedin accordance with the cell temperature, and exposed to the fluidpressure in the container, said cell also having a flexible walldefining the cell space and limiting that area of the said end wallwhich is exposed to the pressure within the cell to less than the areaof said end wall that is exposed within the container; supplementalmeans for impressing a force upon said end wall; and control meansaffected by the position of said end wall.

2. In a device of the character described, a refrigerant container; asealed pressure cell having a flexible wall exposed to the temperaturewithin the container, and having as well an end wall adapted to be movedin accordance with the cell temperature, and exposed tothe fluidpressure in the container, said cell also having a flexible walldefining the cell space and limiting that area of the said end wallwhichis exposed to the pressure within the cell to less than the area ofsaid end wall that is exposed within the operation of said valve,andmeans separate from said port, defining a throttling orifice in theoutlet side of the valve. I

' WILLIAM A. RAY.

